Mould Issues

[r803]

Hi,

I posted a few months ago about mould & damp issues in the living room of my property. After some advise, I got more ventilation in there. Initially there was a window which wouldn't open (Not sure why, bought it like this) but I've had a new window put in which has a trickle vent. We keep this opened throughout the day. After getting ventilation and putting a dehumidifier, we redecorated the room. Cleaning down the walls with soap solution, putting damp seal paint and then painting normally.

However just weeks after doing this work, the mould has started appearing.

There's an extractor fan in the room as well (Apparently a corner within the room used to be a small toilet) however this doesn't work so probably need to get it looked at.

I've bought a humidity meter and typically the room shows at around 70% humidity but sometimes can be above 80% when cooking in the kitchen. I've also noticed steam building up on the walls of this room at times, initially I thought it was a water leak but it seems that it may be from the kitchen when cooking.

I've attached a few pics. The indoor ones are from a week or so ago, the mould is now visibly more than shown in the picture.

The outdoor picture is the exterior of one of the walls that has mould. Where it's green at the bottom, that's where some of the mould is on the inside. Not sure what this could be and if it's related.

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Any help or advice would be appreciated.

Thanks

[r803]

Some indoor pics

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[Firewatcher]

Living room should be around the 40 to 60% mark, pickling is from the high humidity and only takes a few days to form. Unlikely to be a problem with the outside wall. Certainly there is a great deal of moisture created in a kitchen, and you need to try and extract it preferably at source rather than allow it to go all over the house. Helps if you don't leave things boiling vigorously as many people do - just creates loads of steam but doesn't cook any quicker. The damp proof paint works both ways, and keeps moisture in as well, so will condense on the inside and form the mould.
Trickle vents give very low level ventilation unless it is breezy so if you can get the fan replaced it will help.
It may just be the kitchen, but worth checking the floor is dry, no pipework leaks or excessive damp anywhere.
Pete

[wine~o]

Sounds like you didn't kill/treat the original mould spores before redecorating, something like HG mould killer.

[Surveyorman]

Echoing some of what Firewatcher has advised, you need to review your moisture management that exists within the property specifically in the moisture producing rooms i.e. kitchen, bathroom and utility room. Moist air is created by many factors such as the lack of adequate ventilation and exacerbated by cooking, bathing and the drying of clothes over radiators etc.

With very rare exceptions the air always has a moisture content which greatly increases during cooking and bathing/showering etc.
Warm air is capable of carrying a larger amount of moisture than cool air. The reason you are seeing the mould form on this particular wall is because (judging by the photos) it is an external wall and therefore has a cooler surface than other areas in the house (where you are not seeing mould form) You will often see mould form around the lower parts of a wall (as is the case with you) near the floor wall junction as this too (unless you had under floor heating) is often a cooler space. As air laden moisture reaches this wall the temperature drops until the relative humidity reaches what is known as dew point (This is the temparture at which condensation occurs) Mould usually appears as unsightly growths in various colours green, yellow, pink, black, grey or white and will form over wall ceiling and floor surfaces and sometimes over clothes and all other fabrics particularly leather.

Consideration of resolve must include controlling the Relative Humidity within the property by adequate extraction of the moist air in a controlled and effective manner. For this purpose I would recommend the installation of a humidity tracking fan (aslo known as a humidistat fan) to control the internal atmosphere and ensure the Relative Humidity is maintained below the optimum 70% at which point mould will form and subsequently release spores. There are hundreds of extraction units in the market place however these are one of those things where you really only get what you pay for “cheaper options are most unlikely to provide little if any benefit”. Incidentally, current Building Regulations stipulate that Bathroom fans should extract @ 15 ltrs per second and Kitchen fans @ between 30 and 60 litres per second dependent on their close proximity with the cooker. Envirovent and Nuaire are examples of two companies that produce the units that I mention above.

Any mould growth over the surface finishes can be removed by a specialist mould wash and enhanced protection by paint and wallpaper paste additives which again can be sourced and purchased from specialist companies.

Condensation is the most common form of “dampness” within UK properties and you will digest from what I have mentioned above above that its causation and control is not about one particular subject but many. There are lots of helpful resources available on the internet regarding this subject. The good news is that you can resolve this problem with relatively little disruption. It often takes a combination of making some lifestyle alterations and investing in some decent extractor fans in the key rooms. Good luck!

[wes56]

your pics show past DPC injection holes. that chemical DPC was injected to deal with rising damp not condensation. typical stupidity from damp people because that house would already have a built in DPC. anyhow the injection it didn't work, you can see damp staining two courses above the line of holes. that outsside skin is part of a cavity wall and its usually useless injecting an outside skin.
the cavity could also be bridged with rubbish from bricklaying or failing CWI if you have any CWI.
ther are signs of rising damp inside the room and the skirting looks to be starting to rot, there's also indications of past remedial plastering.

[Surveyorman]

Wes56, I agree with many of your observations apart from the last line of your last message. Unless I have missed something, there are definitely no signs of "rising damp" inside the room. As you're probably aware given the age that we suspect this building to be, it will have a physical damp proof course and most likely be of cavity wall construction. With this in mind it is highly unlikely that rising damp is occurring. It is possible that there is bridging of the damp proof course but we can't really offer a solid conclusion without further information eg floor type, location of original DPC, height of external ground levels in relation to the original DPC, whether or not CWI is present etc etc.

All of the information offered by the OP at this point points towards a condensation issue. The only exception to this is the staining to the external brick work.

[wes56]

yeah, you've missed something. The signs are there if you look with experienced eyes.
Rising damp is just as likely to be in a cavity wall as a solid wall.
There are condensation issues but my previous post was obviously directed towards a rising damp issue only - other posts had addressed the condensation issue.

[Surveyorman]

As I’ve said, I agree with the majority of what you are saying Wes but you are wrong in saying that their are signs rising damp in these photos (unless you are looking at different photos to me). There are no signs of rising damp whatsoever in the internal pictures of this room and given that we assume the age of the building to be relatively modern judging from the external pics (certainly built within at least the latter part of the last century), it is highly unlikely that rising damp would be affecting these walls.

[wes56]

No problems with my photo's.
So you consider that cavity walls built in the "latter part of the last century" are "highly unlikely" to have been affected by rising damp?
Thats a strange observation from a user name claiming to be a "Surveyorman"?

[moderator2]

wes56, and Surveyorman,

Please try to play nicely. You may have different opinions or ideas regards the OP's issues, I'm sure all of them will have some validity. The last thing we need is a

[shirty_sleeve]

Remove the mould using either a bleach or specific mould killing formula -DO wear protective face mask, gloves and keep the door to the room shut whilst using the mould killing soloution. I would use a steam carpet cleaner on carpets and fabrics that can not be removed or washed.

Once cleaned and dry, with suitable surface preperation -
Get the effected walls lined with a decent thermal liner and finish with a paintable non woven lining paper. You can for a belt 'n' braces approach finish with an anti mould paint or add some anti mould formula to most standard emulsion paints.

Try to keep the chemical use down to bare essentials -

The chances are it is just indoor moisture condensing on a cold wall - you can litterly spend many hundreds, even thousands of pounds fannying around when actually you just need to divert the condensation away from the cold spot.

A decent dehumidifier can work wonders in the right conditions, but definately keep the humidty down.